Re: [PATCH v1 1/2] exec/ram_addr: add dirty arg to cpu_physical_memory_set_dirty_lebitmap()

[Cédric Le Goater]

On 5/23/23 17:12, Joao Martins wrote:

In preparation to including the number of dirty pages in the
vfio_get_dirty_bitmap() tracepoint, return the number of dirty pages in the
range passed by @dirty argument in cpu_physical_memory_set_dirty_lebitmap().

For now just set the callers to NULL, no functional change intended.

Why not return the number of dirty pages to be consistent with
cpu_physical_memory_sync_dirty_bitmap () ?

bitmap_count_one() would also give the same result but at the cost
of extra loops.

Thanks,

C.

Signed-off-by: Joao Martins <joao.m.mart...@oracle.com>
---
  accel/kvm/kvm-all.c     |  2 +-
  hw/vfio/common.c        |  4 ++--
  include/exec/ram_addr.h | 10 +++++++++-
  3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index cf3a88d90e92..1524a34f1786 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -559,7 +559,7 @@ static void kvm_slot_sync_dirty_pages(KVMSlot *slot)
      ram_addr_t start = slot->ram_start_offset;
      ram_addr_t pages = slot->memory_size / qemu_real_host_page_size();

- cpu_physical_memory_set_dirty_lebitmap(slot->dirty_bmap, start, pages);

+    cpu_physical_memory_set_dirty_lebitmap(slot->dirty_bmap, start, pages, 
NULL);
  }

static void kvm_slot_reset_dirty_pages(KVMSlot *slot)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 78358ede2764..dcbf7c574d85 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -587,7 +587,7 @@ static int vfio_dma_unmap_bitmap(VFIOContainer *container,
      ret = ioctl(container->fd, VFIO_IOMMU_UNMAP_DMA, unmap);
      if (!ret) {
          cpu_physical_memory_set_dirty_lebitmap(vbmap.bitmap,
-                iotlb->translated_addr, vbmap.pages);
+                iotlb->translated_addr, vbmap.pages, NULL);
      } else {
          error_report("VFIO_UNMAP_DMA with DIRTY_BITMAP : %m");
      }
@@ -1773,7 +1773,7 @@ static int vfio_get_dirty_bitmap(VFIOContainer 
*container, uint64_t iova,
      }

cpu_physical_memory_set_dirty_lebitmap(vbmap.bitmap, ram_addr,

-                                           vbmap.pages);
+                                           vbmap.pages, NULL);

trace_vfio_get_dirty_bitmap(container->fd, iova, size, vbmap.size,

                                  ram_addr);
diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index f4fb6a211175..07bf9e1502b6 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -335,7 +335,8 @@ static inline void 
cpu_physical_memory_set_dirty_range(ram_addr_t start,
  #if !defined(_WIN32)
  static inline void cpu_physical_memory_set_dirty_lebitmap(unsigned long 
*bitmap,
                                                            ram_addr_t start,
-                                                          ram_addr_t pages)
+                                                          ram_addr_t pages,
+                                                          unsigned long *dirty)
  {
      unsigned long i, j;
      unsigned long page_number, c;
@@ -380,6 +381,10 @@ static inline void 
cpu_physical_memory_set_dirty_lebitmap(unsigned long *bitmap,
                          }
                      }

+ if (dirty) {

+                        *dirty += ctpopl(temp);
+                    }
+
                      if (tcg_enabled()) {
                          qatomic_or(&blocks[DIRTY_MEMORY_CODE][idx][offset],
                                     temp);
@@ -411,6 +416,9 @@ static inline void 
cpu_physical_memory_set_dirty_lebitmap(unsigned long *bitmap,
                  if (unlikely(global_dirty_tracking & 
GLOBAL_DIRTY_DIRTY_RATE)) {
                      total_dirty_pages += ctpopl(c);
                  }
+                if (dirty) {
+                    *dirty += ctpopl(c);
+                }
                  do {
                      j = ctzl(c);
                      c &= ~(1ul << j);